Bladed cutting tool with removable and replaceable blade

ABSTRACT

A bladed cutting tool consisting of a handle slotted to receive and releasably retain and hold a cutting blade, by and in response to reciprocation within the handle of blade holding and releasing means.

United States Patent Hasegawa 5] Nov. 25, 1975 BLADED CUTTING TOOL WITH[56] References Cited REMOVABLE AND REPLACEABLE BLADE UNITED STATESPATENTS [75] Inventor; Shigeki Hasegawa, Ming, Japan 1,448,730 3/1923Davis 30/337 2,109,108 2/1938 [73] Assignee: Feather Kogyo K.K., Japan2,256,032 9/1941 Holoman App]. No.: 491,853

Foreign Application Priority Data Mar. 4, 1974 Japan 49-25741 U.S. Cl30/338; 30/342 Int. Cl. B268 l/00 Field of Search 30/337, 338, 339, 329,

Primary Examiner-Al Lawrence Smith Assistant Examiner-Robert C. WatsonAttorney, Agent, or FirmOtto John Munz [57] ABSTRACT A bladed cuttingtool consisting of a handle slotted to receive and releasably retain andhold a cutting blade, by and in response to reciprocation within thehandle of blade holding and releasing means.

5 Claims, 12 Drawing Figures US. Patent Nov. 25, 1975 SheetlofS3,921,289

FIG.]

U.S. Patent Nov. 25, 1975 Sheet20f5 3,921,289

Patent Nov. 25, 1975 Sheet30f5 3,921,289

US. Patent Nov. 25, 1975 Sheet 5 of5 3,921,289

FI G.9

FIG.10 FI G 11 5 M r WM 56 V I2 l4 FIG.12

BACKGROUND OF THE INVENTION DESCRIPTION OF THE PREFERRED EMBODIMENTReferring in particular to FIG. 3, the blade holder This inventionrelates to a cutting instrument consistcomprises an assembly indicatedat 10. From FIG. 1 it ing essentially of a handle having means toreceive and releasably retain and hold the end of a blade.

It is the chief purpose and aim to provide an instrument as aforessaidby which blades of various shapes, sizes and purposes may be substitutedin and firmly held by one and the same handle.

A further object is to provide an instrument as aforesaid, whereinchange of blades may be instantly and readily made without the use of atool.

Another object is to provide a tool of the nature stated which is neat,attractive and smooth in appearance and in which the blade releasemechanism is concealed within the handle, except for an actuating knobforming a smooth and attractive continuation of the rearward end of thehandle.

A further object is to afford a handle which is formed of two similarhalves having planar surfaces contacting at an interface, which surfacesare grooved or channeled to conjointly define and form chambersaccomodating the blade-release and retaining mechanism.

Other objects and advantages will become apparent to those skilled inthe art, after a study of the following detailed description, inconnection with the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an exploded perspective viewof the blade holder or handle with halves separated to show the bladeretaining and releasing mechanism, the rearward portion of a blade beingshown in dot-dash lines;

FIG. 2 is a vertical longitudinal section showing one handle portion,the blade holding mechanism being retracted to position releasing ablade the rearward end .of which is shown in dot-dash lines;

FIG. 3 is a perspective view showing the fully assembled handle and therearward end of a blade emplaced therein but with the knob of theblade-holding means retracted to release position.

FIG. 4 is a vertical longitudinal section similar to FIG. 2 but showinghow a blade indicated in dot-dash lines, is inserted into the handle;

FIG. 5 is a perspective view like FIG. 3 but showing how the releaseknob at the end of the handle, may be rotated to retain the releasemechanism retracted;

FIG. 6 is a side elevation to reduced scale, showing one side of thehandle with a blade secured therein;

FIG. 7 is an elevational view like FIG. 6, of the other side of thehandle with a blade secured thereto;

FIG. 8 is a top plan view of a fully assembled handle and blade;

FIG. 9 is a bottom plan view of the assembled instrument;

FIG. 10 is an end view looking from left to right, FIG. 6;

FIG. 11 is an end view looking from right to left, FIG. 6; and

FIG. 12 is a central longitudinal section through the assembledinstrument, taken in a plane normal to the plane of FIG. 8 and showingthe holding mechanism in operating position.

is noted that the handle consists of two similar halves l4, separable ina plane generally coincident withthe plane of a flat blade 12. Thehandle portions may be of wood, plastic, metal or other suitable rigidmaterial.

0 The two halves are rigidly secured together by a numher of machinescrews 38, three being shown in the model selected for illustration.Each screw fits in and extends through its respective hole 40 in onehandle portion and threads into a hole in the opposite section, as isclear from inspection of FIG. 1. Each hole 40 is counterbored at itsoutward end so that all screw heads are essentially flush with thesurface of the handle.

The handle halves 14 are formed, each with a semicylindrical groove orchannel 22 which mate when the handle is assembled, to form a guidewayfor slidably mounting in the axial or longitudinal direction, a push rod16, shown as cylindrical. At their forward ends channels 22 are enlargedor counterbored as at 24, FIGS. 1, 2 and 4, to jointly form a chamber inwhich slidably fits a circular flange 46 and which may be integral withrod 16 at the forward end thereof. A coil spring 48 surrounds rod 16 fora free fit in counterbore 24. The parts are constructed and arranged sothat in the assembled handle the spring abuts flange 46 at one end andat its rearward end engages the shoulder formed by and between grooves22 and counter-bore 24. The spring acts continuously to urge rod 16forwardly into its blade-locking position.

At their forward ends the blade halves are formed with integralforwardly-extending projections 34 each having a flat recess 26 in itsinner face. Each recess has a depth or dimension transversely of thehandle, of about one-half the thickness of the blade to be usedtherewith, so that there is thus formed a cavity or slot into which theend of blade 12 may smoothly fit. As

seen from FIG. 1 the slot formed conjointly by recesses v 26 is shapedto conform to the end of the blade. A pin 28 is fixed with and protrudesfrom the recess in one handle half 14 and in the assembled instrumentfits a bore 36 in the opposite portion. This assures accurateregistration of the halves and as will be subsequently explained the pinalso fits and receives a notch 30 in blade 12 when the latter is fullyemplaced. The blade is thereby positively held against longitudinal oraxial movement in its slot in the handle. It is contemplated in certainmodels more than one pin like 28 may be provided, with each pin fittingits own slot in the blade.

The halves of the handle are formed at the forward end of counterbore24, with notches which register and conjointly form or define apassageway 32 opening into the rearward end of recesses 26 forming thebladereceiving slot. The passageway is so shaped as to re cieve with asmooth sliding fit, a lug or nose 44 integral with or otherwise rigidlyaffixed to the forward end of rod 16. It is important to note from FIG.2 that the for ward portion of nose 44 has generally fiat parallel faceswhich make this portion of essentially uniform thickness in the verticaldirection, which thickness may gradually increase at and along therearward portion. The transverse dimension of the nose may be uniformand is greater thanthe corresponding dimension of the blade-receivingslot. Thus when the nose is in its forward or blade-locking position itis fixed against turning about the axis of rod 16, by reason of itssmooth fit within passageway 32. Further, as is clear from FIG. 12, whenrod 16 is moved by spring 48 into its forward or locking position, nose44 fits smoothly within a correspondingly-shaped notch 60 in therearward edge of blade 12 and thus prevents the latter from downwardtranslation and/or pivoting in its slot in the handle.

At its end remote from nose 44, rod 16 is axially drilled and threadedas at 42. so that a release knob 18 may be secured thereto by a screw 56passing through a hole 52 in the knob and threaded into the rod. Thehandle halves are recessed at their outward rear surfaces as indicatedat 57. FIGS. 1, 3 and 5. The knob has spaced forwardly-extending lugs 54integral therewith each of which has a smooth fit in a respective one ofthe recesses 57 when the knob is in its forward or bladelockingposition. The angular relation of nose 44 and lugs 54 is such that whenthe nose is in the position of FIGS. 1, 2, 3 and 12 about the axis ofrod 16, the lugs are in registration. each with a respective recess 57,thus enabling spring 48 to move the nose forwardly into fullblade-retaining position. But when the knob is grasped, axiallytranslated rearwardly against the urge of the spring, to retract lugs 54from their recesses. the assembly comprising the knob, rod and nose maybe rotated 90 to a second position wherein when the knob is released.the ends of lugs 54 engage the contiguous end of the handle and thus actto retain the nose in blade-releasing or retracted position. Theoperation and use of the invention will be generally clear from theforegoing description. Starting with the blade and handle separated,knob 18 is retracted and turned 90 as previously explained. Then theblade with its forward end tilted downwardly somewhat, is

slid into its slot in the handle until notch 60 registers withpassageway 32. By tilting or moving the blade slightly upwardly itsnotch 30 fits over and about pin 28. Then knob 18 is slightly retracted,rotated 90 and released so that spring 48 may move the nose forwardly toseat smoothly and firmly in notch 60. At the same time each lug 54 seatsin its recess 57. The blade is then firmly but releasably locked to thehandle.

The advantages of the invention are numerous. A blade can be easilyremoved for sharpening, straightening or replacement with a new or usedblade. No tools are required for the interchange. Blades of variouslengths, shapes and purposes can be readily and quickly substituted. Theforward extensions 34 at and along the top of each blade half 14 arevery useful, especially for long blades because these conjointly form acontinuation of the upper edge of the blade-recieving slot of the handleand permit increased force or leverage on the blade, downwardly in thecutting direction. So long as the rearward end of each blade is properlyshaped and notched, it can have any selected length within practicablelimits and be designed and shaped for a variety of purposes such as insurgery, woodworking, household use in slicing and cutting and numerousother uses and purposes. The blade may also be made with a toothed edgefor sawing. Where a collection of blades is accumulated for use with asingle handle, all blades may be sharpened at the same time and amaterial saving in costs of servicing thus effected.

The handle is simple to assemble. With one handle half held as in FIG.1, rod 16 is disposed in groove 22 thereof, the rearward end of spring48 is urged slightly forwardly until the entire spring is seated incounterbore 24. With the spring thus slightly compressed the other halfis moved into registering contact with the first half and'screws 38 areinserted and threaded down until the two halves are in unitary contact.Disassembly of the handle for repairs or servicing is equally easy.

Terms such as vertical, horizontal', laterally, etc. as used in thespecification and claims, refer to the positions of the parts as shownin the drawing and are not to be interpreted as limiting use of theinstrument to any particular position.

As numerous changes in shape, size and relation of component parts willbe obvious to those skilled in the art after a study of the foregoingdisclosure, the disclosure is to be taken in an illustrative rather thana limiting sense.

I claim:

1. A handle for releasably holding a flat blade and comprising twoessentially similar halves secured together at an essentially planarinterface and conjointly defining a central longitudinal passageway anda bladereceiving slot forwardly of the passageway, a rod axiallyslidable in and along said passageway, said rod extending rearwardly toprotrude slightly from the end of the handle, a nose fixed with theforward end of said-rod and axially movable with the same from a firstforward position engageable with a blade fitting said slot, to a secondretracted position free of .the blade, a knob fixed to said protrudingend and operable to move said rod and nose between first and secondpositions, and lug means carried by said knob to engage said handle andhold said rod in second and retracted position when said rod,-nose andknob are retracted and rotated as a unit through a predetermined angle.

2. The handle of claim 1, said passageway being counterbored from itsforward end to form an annular shoulder, and a coil spring surroundingsaid rod and fitting said counterbore to engage at its respective endswith a flange fixed with said rod and with said shoulder to thereby urgesaid nose, rod and knob into said first and blade-holding position. V

3. The handle of claim 2, said lug'means when said knob is in firstposition, engaging in recess means in said handle to releasably lock theknob against rota-- tion. I

4. The combination with a handle for releasably holding a flat blade andhaving a central longitudinal passageway and a blade-receiving slotforwardly of the passageway, a rod axially slidable in said passageway,a nose fixed with the fixed with the forward end of said rod and axiallymovable with the same, from a first forward position engageable with ablade fitting said slot, to a second retracted position free of theblade, manually operable means fixed with the rearward end of said rodfor moving the same to and retaining it in second position, of a bladefitting said slot, a pin fixed in said handle and extending across saidslot transversely thereof, and through a first notch in the upper edgeof said blade, there being a second notch in the rearward edge of saidblade in which said nose engages only when said nose and rod are infirst and forward position, said nose being retracted free of saidsecond notch when in second position.

5. The combination of claim 4, said handle having a forward projectionextending over, along and in contact with the contiguous upper edge ofthe blade,

said pin being located forwardly in said extension.

1. A handle for releasably holding a flat blade and comprising twoessentially similar halves secured together at an essentially planarinterface and conjointly defining a central longitudinal passageway anda blade-receiving slot forwardly of the passageway, a rod axiallyslidable in and along said passageway, said rod extending rearwardly toprotrude sLightly from the end of the handle, a nose fixed with theforward end of said rod and axially movable with the same from a firstforward position engageable with a blade fitting said slot, to a secondretracted position free of the blade, a knob fixed to said protrudingend and operable to move said rod and nose between first and secondpositions, and lug means carried by said knob to engage said handle andhold said rod in second and retracted position when said rod, nose andknob are retracted and rotated as a unit through a predetermined angle.2. The handle of claim 1, said passageway being counterbored from itsforward end to form an annular shoulder, and a coil spring surroundingsaid rod and fitting said counterbore to engage at its respective endswith a flange fixed with said rod and with said shoulder to thereby urgesaid nose, rod and knob into said first and blade-holding position. 3.The handle of claim 2, said lug means when said knob is in firstposition, engaging in recess means in said handle to releasably lock theknob against rotation.
 4. The combination with a handle for releasablyholding a flat blade and having a central longitudinal passageway and ablade-receiving slot forwardly of the passageway, a rod axially slidablein said passageway, a nose fixed with the fixed with the forward end ofsaid rod and axially movable with the same, from a first forwardposition engageable with a blade fitting said slot, to a secondretracted position free of the blade, manually operable means fixed withthe rearward end of said rod for moving the same to and retaining it insecond position, of a blade fitting said slot, a pin fixed in saidhandle and extending across said slot transversely thereof, and througha first notch in the upper edge of said blade, there being a secondnotch in the rearward edge of said blade in which said nose engages onlywhen said nose and rod are in first and forward position, said nosebeing retracted free of said second notch when in second position. 5.The combination of claim 4, said handle having a forward projectionextending over, along and in contact with the contiguous upper edge ofthe blade, said pin being located forwardly in said extension.